This present disclosure relates to a motion control device, such as a slider, suitable for moving an object, such as a camera, along a defined path. Sliders are well known in the photographic and cinematographic arts. A slider is typically defined by a rail system having a pair of parallel rails with a slider tray carried on the rails and a camera is mounted to the slider tray. Sliders are useful for producing a camera shot where the camera needs to be moved along a defined path. Sliders may define a straight or curved path, and allow for a smooth and repeatable camera movement. It is common for motors to drive the slider so that the slider moves at a defined rate along the rails. Such motors are capable of providing precise movements at variable speeds.
In some instances, it is desired to have the camera not only move along a defined path, but to also have the camera pan as it moves. Previously, panning required use of a motor which rotated the camera at a precise rate and a precise time relative to the motion of the slider as it moves on the rails. Such motors are expensive and require a high degree of skill, and considerable time to program for a given shot to ensure the camera pans and slides in unison.
One common camera movement which illustrates the difficulty of coordinating the pan and slide movements is a “fixed point shot.” In such a shot, the desired effect is to have the camera remain focused on a given stationary point spaced some distance from the slider as the camera moves along the rails. In order for the camera to point at the given point during the travel along the rails, the camera must rotate at a rate such that at any given position along the rails, the camera is pointed directly at the given point. While previous slider systems are capable of producing such a shot, they are only able to do so if set up by a highly skilled technician who carefully calibrates each of the respective motors. Therefore, an improved panning slider is needed.